团簇NiPS_(3)的成键及稳定性分析

Analysis of Bonding and Stability for Cluster NiPS

为了对团簇NiPS_(3)的成键情况和稳定性进行研究,以密度泛函理论为理论基础,在B3LYP/def2-tzvp水平下,对团簇NiPS _(3)的初始构型进行优化计算,最终得到二、四重态下共10种优化构型.通过对各原子间平均键级、平均键长和成键键级贡献率三方面对团簇NiPS_(3)的成键情况进行分析,发现P—S键的平均键级较大,平均键长较短,说明在团簇NiPS_(3)中P—S键的成键能力最强,成键强度最大;各原子之间成键键级贡献率的大小顺序为P—S键>Ni—S键>S—S键>Ni—P键.通过对各构型能量参数和HOMO-LUMO能隙差两方面对团簇NiPS_(3)的稳定性进行分析,发现构型1^((2))的校正能(E_(ZEP))最低,吉布斯自由能变(ΔG)最小,结合能(E_(BE))最大,相较其他构型更加容易形成,且其HOMO-LUMO能隙差最大,故在构型1^((2))中电子跃迁较难发生,即构型1^((2))的热力学稳定性和化学稳定性均为最优.

In order to investigate the bonding situation and stability of cluster NiPS_(3),the initial configuration of cluster NiPS_(3) was optimized and calculated at the level of B3LYP/def2-tzvp based on the density function theory,and finally a total of 10 optimized configurations were obtained in the two-quadruplet state.The average bonding level,average bond length and bonding level contribution among the atoms were analyzed,and it was found that the average bonding level of the P—S bond was larger and the average bond length was shorter,indicating that the bonding ability of the P—S bond was the strongest and the bonding strength was the largest in the cluster NiPS_(3);the order of the bonding level contribution among the atoms was P—S bond>Ni—S bond>S—S bond>Ni—P bond.By analyzing the stability of cluster NiPS_(3) in terms of both energy parameters of each configuration and HOMO-LUMO energy gap difference,it is found that configuration 1^((2)) has the lowest correction energy(E_(ZEP)),the smallest Gibbs free energy change(ΔG),and the largest binding energy(E_(BE)),which is easier to form compared with other configurations,and its HOMO-LUMO energy gap difference is the largest.Therefore,the electron transition in configuvation 1^((2)) is difficult,i.e.,the thermodynamic stability and chemical stability of conformation 1^((2)) are both optimal.